A coated decorative sheet comprising a substrate sheet, such as paper or a plastic sheet, having thereon a color solid layer, a pattern layer with a pattern of a grain or the like printed thereon, and a top coat for protecting the surface of the decorative sheet has hitherto been known as a decorative sheet for use in interior decoration of buildings, surface decoration of fittings and fixtures, interior decoration of vehicles and other applications.
An attempt to express three-dimensional effect has been made to prepare decorative paper having realistic appearance close to the actual object. For the formation of concaves and convexes used in decorative sheets, for example, a method has been proposed wherein a pattern having different gloss is printed to form, on the same plane (within the surface), a visual combination of a gloss region with a non-glass region, thereby forming pseudo concaves and convexes through the utilization of such an illusion that the gloss region is visually seen as a convex with the non-gloss region being visually seen as a concave. A conventional method for the formation of pseudo concaves and convexes using a gloss region and a non-gloss region is disclosed in Japanese Patent Publication No. 41364/1976. According to this method, patterns are formed using a plurality of inks different from each other in particulate solids, and a solvent type top coat is formed thereon to create a difference in penetration of the coating composition among patterns to form pseudo concaves and convexes through the utilization of a gloss-non-gloss pattern.
In the conventional concave-convex pattern by creating a difference in penetration of the coating composition, however, the difference in level between concave and convex is small, and the boundary between concave and convex is not sharp. Therefore, the visual three-dimensional effect is unsatisfactory. Further, the conventional decorative sheet having a concave-convex patter is likely to cause surface scratches, and then has a problem of durability.
Further, Japanese Patent Publication No. 14824/1989 proposes a method for the formation of concaves and convexes on the surface of a decorative material which comprises forming, on a substrate, patterns using a penetrable coating composition and a solvent-resistant ink and coating thereon a top coat coating composition comprising an electron beam curing resin, followed by curing to form concaves and convexes through the utilization of a difference in penetration.
According to the finding of the present inventors, however, since the solvent-resistant ink per se contains a pigment (inorganic particles), the penetration unavoidably occurs, leading to a reduction in difference in penetration between the solvent-resistant ink and the penetrable coating composition. This renders reduction difference the difference in level between concaves and convexes unsatisfactory, and the reality and the three-dimensional effect are poor. Use of a solvent-resistant ink with the pigment being removed therefrom can emphasize the difference in penetration between the pattern of the penetrable coating composition and the pattern of the solvent-resistant ink. In this case, however, the pattern of the solvent-resistant ink is colorless, and this is unacceptable from the viewpoint of reproduction of appearance and design.
Accordingly, it is an object of the present invention to provide a synchronously embossed decorative sheet which has excellent three-dimensional effect in sharp tune with a pattern layer and, at the same time, is less likely to cause scratches, and to provide a process for producing the same.